Objectives. To explore the therapeutic potential of combining bone marrow-derived mesenchymal stem cells (BM-MSCs) and hydroxyapatite (HA) granules to treat nonunion of the long bone. Methods. Ten patients with an atrophic nonunion of a long bone fracture were selectively divided into two groups. Five subjects in the treatment group were treated with the combination of 15 million autologous BM-MSCs, 5g/cm. 3. (HA) granules and internal fixation. Control subjects were treated with iliac crest autograft, 5g/cm. 3. HA granules and internal fixation. The outcomes measured were post-operative pain (visual analogue scale), level of functionality (LEFS and DASH), and radiograph assessment. Results. Post-operative pain evaluation showed no significant differences between the two groups. The treatment group demonstrated faster initial radiographic and functional improvements. Statistically significant differences in functional scores were present during the first (p = 0.002), second (p = 0.005) and third (p = 0.01) month. Both groups achieved similar outcomes by the end of one-year follow-up. No immunologic or neoplastic side effects were reported. Conclusions. All cases of nonunion of a long bone presented in this study were successfully treated using autologous BM-MSCs. The combination of autologous BM-MSCs and HA granules is a safe method for treating nonunion. Patients treated with BM-MSCs had faster initial radiographic and functional improvements. By the end of 12 months, both groups had similar outcomes. Cite this article: H.D. Ismail, P. Phedy, E. Kholinne, Y. P. Djaja, Y. Kusnadi, M. Merlina, N. D. Yulisa. Mesenchymal stem cell implantation in atrophic nonunion of the long bones: A translational study. Bone Joint Res 2016;5:287–293. DOI: 10.1302/2046-3758.57.2000587

Our aim was to develop a clinically relevant model of atrophic nonunion in the rat to test the hypothesis that the vessel density of atrophic nonunion reaches that of normal healing bone, but at a later time-point. Atrophic nonunion is usually attributed to impaired blood supply and is poorly understood. We determined the number of blood vessels at the site of an osteotomy using immunolocalisation techniques in both normally healing bones and in atrophic nonunion. At one week after operation there were significantly fewer blood vessels in the nonunion group than in the healing group. By eight weeks, the number in the atrophic nonunion group had reached the same level as that in the healing group. Our findings suggest that the number of blood vessels in atrophic nonunion reaches the same level as that in healing bone, but at a later time-point. Diminished vascularity within the first three weeks, but not at a later time-point, may prevent fractures from uniting

Abstract. Introduction. Skeletal muscle wasting is an important clinical issue following acute traumatic injury, and can delay recovery and cause permanent functional disability particularly in the elderly. However, the fundamental mechanisms involved in trauma-induced muscle wasting remain poorly defined and therapeutic interventions are limited. Objectives. To characterise local and systemic mediators of skeletal muscle wasting in elderly patients following acute trauma. Methods. Experiments were approved by a local NHS Research Ethics Committee and all participants provided written informed consent. Vastus lateralis biopsies and serum samples were taken from human male and female patients shortly after acute trauma injury in lower limbs (n=6; mean age 78.7±4.4 y) and compared to age-matched controls (n=6; mean age 72.6±6.3 y). Atrogenes and upstream regulators (MuRF1; MAFbx; IL6, TNFα, PGC-1α) mRNA expression was assessed in muscle samples via RT-qPCR. Serum profiling of inflammatory markers (e.g. IL6, TNFα, IL1β) was further performed via multiplex assays. To determine whether systemic factors induced by trauma directly affect muscle phenotype, differentiated primary human myotubes were treated in vitro with serum from controls or trauma patients (pooled; n=3 each) in the final 24 hours of differentiation. Cells were then fixed, stained for myogenin and imaged to determine minimum ferret diameter. Statistical significance was determined at P<0.05. Results. There was an increase in skeletal muscle mRNA expression for E3 ligase MAFbx and inflammatory cytokine IL-6 (4.6 and 21.5-fold respectively; P<0.05) in trauma patients compared to controls. Expression of myogenic determination factor MyoD and regulator of mitochondrial biogenesis PGC-1α was lower in muscle of trauma patients vs controls (0.5 and 0.39-fold respectively; P<0.05). In serum, trauma patients showed increased concentrations of circulating pro-inflammatory cytokines IL-6 (14.5 vs. 0.3 pg/ml; P<0.05) and IL-16 (182.7 vs. 85.2 pg/ml; P<0.05) compared to controls. Primary myotube experiments revealed serum from trauma patients induced atrophy (32% decrease in diameter) compared to control serum-treated cells (P<0.001). Conclusion. Skeletal muscle from patients following acute trauma injury showed greater expression of atrophy and inflammatory markers. Trauma patient serum exhibited higher circulating pro-inflammatory cytokine concentrations. Primary human myotubes treated with serum from trauma patients showed significant atrophy compared to healthy serum-treated controls. We speculate a mechanism(s) acting via circulating factors may contribute to skeletal muscle pathology following acute trauma. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

To test and evaluate the effectiveness of local injection of autologous fat-derived mesenchymal stem cells (MSCs) into fracture site to prevent non-union in a clinically relevant model. 5 male Wistar rats underwent the same surgical procedure of inducing non-union. A mid-shaft tibial osteotomy was made with 1mm non-critical gap. Periosteum was stripped around the two fracture ends. Then, the fracture was fixed by ante-grade intramedullary nail. The non-critical gap was maintained by a spacer with minimal effect on the healing surface area. At the same surgical time, subcutaneous fat was collected from the ipsilateral inguinal region and stem cells were isolated and cultured in vitro. Within three weeks postoperatively, the number of expanded stem cells reached 5×10. 6. and were injected into the fracture site. Healing was followed up for 8 weeks and the quality was measured by serial x-rays, microCT, mechanical testing and histologically. Quality of healing was compared with that of previously published allogenic, xenogeneic MSCs and Purified Buffered Saline (PBS) controls. All the five fractures united fully after 8 weeks. There was a progressive increase in the callus radiopacity during the eight-week duration, the average radiopacity in the autologous fat-MSC injected group was significantly higher than that of the allogeneic MSCs, xenogeneic MSCs and the control group, P < 0.0001 for treatment, time after injection, and treatment-time interaction (two-way repeated measure ANOVA). MicroCT, mechanical testing and histology confirmed radiological findings. The autologous fat-MSCs are effective in prevention of atrophic non-union by stimulation of the healing process leading to a solid union. The quality and speed of repair are higher than those of the other types of cell transplantation tested

Virtual mechanical testing is a method for measuring bone healing using finite element models built from computed tomography (CT) scans. Previously, we validated a dual-zone material model for ovine fracture callus that differentiates between mineralized woven bone and soft tissue based on radiodensity. 1. The objective of this study was to translate the dual-zone material model from sheep to two important clinical scenarios: human tibial fractures in early-stage healing and late-stage nonunions. CT scans for N = 19 tibial shaft fractures were obtained prospectively at 12 weeks post-op. A second group of N = 33 tibial nonunions with CT scans were retrospectively identified. The modeling techniques were based on our published method. 2. The dual-zone material model was implemented for humans by performing a cutoff sweep for both the 12-week and nonunion groups. Virtual torsional rigidity (VTR) was calculated as VTR = ML/φ [N-m. 2. /°], where M is the moment reaction, L is the diaphyseal segment length, and φ is the angle of twist. As the soft tissue cutoff was increased, the rigidity of the clinical fractures decreased and soft tissue located within the fracture gaps produced higher strains that are not predicted without the dual zone approach. The structural integrity of the nonunions varied, ranging from very low rigidities in atrophic cases to very high rigidities in highly calcified hypertrophic cases, even with dual-zone material modeling. Human fracture calluses are heterogeneous, comprising of woven bone and interstitial soft tissue. Use of a dual-zone callus material model may be instrumental in identifying delayed unions during early healing when callus formation is minimal and/or predominantly fibrous with little mineralization. ACKNOWLEDGEMENTS:. This work was supported by the National Science Foundation (NSF) grant CMMI-1943287

Anterior cruciate ligament reconstruction (ACLR) using a semitendinosus (ST) autograft, with or without gracilis (GR), results in donor muscle atrophy and varied tendon regeneration. The effects of harvesting these muscles on muscle moment arm and torque generating capacity have not been well described. This study aimed to determine between-limb differences (ACLR vs uninjured contralateral) in muscle moment arm and torque generating capacity across a full range of hip and knee motions. A secondary analysis of magnetic resonance imaging was undertaken from 8 individuals with unilateral history of ST-GR ACLR with complete ST tendon regeneration. All hamstring muscles and ST tendons were manually segmented. Muscle length (cm), peak cross-sectional area (CSA) (cm. 2. ), and volume (cm. 3. ) were measured in ACLR and uninjured contralateral limbs. OpenSim was used to simulate and evaluate the mechanical consequences of changes in normalised moment arm (m) and torque generating capacity (N.m) between ACLR and uninjured contralateral limbs. Compared to uninjured contralateral limbs, regenerated ST tendon re-insertion varied proximal (+) (mean = 0.66cm, maximum = 3.44cm, minimum = −2.17cm, range = 5.61cm) and posterior (+) (mean = 0.38cm maximum = 0.71cm, minimum = 0.02cm, range = 0.69cm) locations relative to native anatomical positions. Compared to uninjured contralateral limbs, change in ST tendon insertion point in ACLR limbs resulted in 2.5% loss in peak moment arm and a 3.4% loss in peak torque generating capacity. Accounting for changes to both max isometric force and ST moment arm, the ST had a 14.8% loss in peak torque generating capacity. There are significant deficits in ST muscle morphology and insertion points following ST-GR ACLR. The ST atrophy and insertion point migration following ACLR may affect force transmission and distribution within the hamstrings and contribute to persistent deficits in knee flexor and internal rotator strength

Abstract. Objective. There is no specific framework for the clinical management of sports related brachial plexus injuries. Necessarily, rehabilitation is based on injury presentation and clinical diagnostics but it is unclear what the underlying evidence base to inform rehabilitative management. Methods. A systematic review of the literature was undertaken in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We applied the PEO criteria to inform our search strategy to find articles that reported the rehabilitative management of brachial plexus injuries sustained while playing contact sports. An electronic search of Medline, CINAHL, SPORTDiscus and Web of Science from inception to 3rd November 2022 was conducted. MESH terms and Boolean operators were employed. We applied an English language restriction but no other filters. Manual searches of Google Scholar and citation searching of included manuscripts were also completed. All study types were considered for inclusion provided they were published as peer-reviewed primary research articles and contained relevant information. Two investigators independently carried out the searches, screened by title, abstract and full text. Two researchers independently extracted the data from included articles. Data was cross-checked by a third researcher to ensure consistency. To assess internal validity and risk of bias, the Joanna Briggs Institute (JBI) critical appraisal tools were utilised. Results. The search generated 88 articles. Following removal of duplicates, 43 papers were evaluated against the eligibility criteria. Nine were eligible for full text review, with the majority of exclusions being expert opinion articles. Eight case reports were included. One article reported three individuals, resulting in data for ten athletes. The mean age was 19.8 years (±4.09). Injuries occurred in five American football players, two wrestlers, two rugby players, and a basketball player. No two studies applied the same diagnostic terminology and the severity of injury varied widely. Burning pain and altered sensation was the most commonly reported symptom, alongside motor weakness in the upper limb. Clinical presentation and management differed by injury pattern. Traction injuries caused biceps motor weakness and atrophy of the deltoid region, whereas compression injuries led to rotator cuff weakness. In all cases treatment was separated into acute and rehabilitative management phases, however the time frames related to these differed. Acute interventions varied but essentially entailed soft tissue inflammation management. Rehabilitation approaches variously included strengthening of shoulder complex and cervical musculature. Return-to-play criteria was opaque. The methodological quality of the case reports was acceptable. Four met all nine of the JBI evaluation criteria, and a further three met at least 75% of items. Conclusion(s). There is a distinct lack of evidence supporting rehabilitation management of sports related brachial plexus injury. Through systematic review we found only eight reports, representing ten individual case studies. No trials, cohort studies, or even retrospective registry-based studies are available to inform clinical management, which, necessarily, is driven by expert opinion and application of basic rehabilitation principles. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Disturbed muscular architecture, fatty infiltration and muscular atrophy remain irreversible in chronic rotator cuff tears (RCT) even after repair. Poly-[ADP-ribose]-polymerase 1 (PARP-1), a nuclear factor involved in DNA damage repair, has shown to be a key element in the up-regulation of early muscle inflammation, atrophy and fat deposition. We therefore hypothesized that the absence of PARP-1 would lead to a reduction in muscular architectural damage, early inflammation, atrophy and fatty infiltration subsequent to combined tenotomy and neurectomy in a PARP-1 knock-out mouse model. PARP-1 knock-out (KO group) and standard wild type C57BL/6 (WT group) mice were randomly allocated into three different time points (1, 6 and 12 weeks, total n=72). In all mice the supraspinatus (SSP) and infraspinatus (ISP) tendons of the left shoulder were detached and the SSP muscle was denervated according to a recently established model. Macroscopic muscle weight analysis, retraction documentation using macroscopic suture, magnetic resonance imaging, immunohistochemistry gene expression analysis using real time qPCR (RTqPCR) and histology were used to assess the differences in muscle architecture, early inflammation, fatty infiltration and atrophy between knock out and wild type mice in the supraspinatus muscle. The SSP did retract in both groups, however; the KO muscles and tendons retracted less than the WT muscles (2.1±21mm vs 3.4±0.41mm; p=0.02). Further assessment of muscle architecture demonstrated that the pennation angle was significantly higher in the KO groups at 6 and 12 weeks (28±5 vs 36±5 and 29±4 vs 34±3; p<0.0001). Combined Tenotomy and neurectomy resulted in a significant loss of muscle mass in both groups compared to the contralateral unoperated side (KO group 62±11% and WT group 52±11%, p=0.04) at 6 weeks. But at 12 weeks postoperatively, there was a significant increase in muscle mass to near normal levels in KO group compared to the WT group (14±6% and 42±7% lower muscle mass respectively; p<0.0001) and less fatty infiltration (12.5 ± 1.82% and 19.6 ± 1.96%, p=0.027). Immunohistochemistry revealed a significant decrease in the expression of inflammatory, apoptotic, adipogenic and muscular atrophy genes at both the 1 week and 6 weeks time points, but not at 12 weeks in the KO group compared to the WT group. This was confirmed by histology. Our study is the first to show that knocking out PARP-1 leads to decreased loss of muscle architecture, early inflammation, fatty infiltration and atrophy after combined tenotomy and neurectomy of the rotator cuff muscle. Although the macroscopic muscles reaction to injury is similar in the first 6 weeks, its ability to regenerate is much greater in the PARP-1 group leading to a near normalization of the muscle substance and muscle weight, less retraction, and less fatty infiltration after 12 weeks

There is a growing trend towards using pre-clinical models of atrophic non-union. This study investigated different fixation devices, by comparing the mechanical stability at the fracture site of tibia bone fixed by either intramedullary nail, compression plate or external fixator. 40 tibias from adult male Wistar rats' cadavers were osteotomised at the mid-shaft and a gap of 1 mm was created and maintained at the fracture site to simulate criteria of atrophic non-union model. These were divided into five groups (n=8 in each): the first group was fixed with 20G intramedullary nail, the second group with 18G nail, the third group with 4-hole plate, the fourth group with 6-hole plate, and the fifth group with external fixator. Tibia was harvested by leg disarticulation from the knee and ankle joints, the soft tissues were carefully removed from the leg, and tibias were kept hydrated throughout the experiment. Each group was then subdivided into two subgroups for mechanical testing: one for axial loading (n=4) and one for 4-point bending (n=4). Statistical analysis was carried out by ANOVA with a fisher post-hoc comparison between groups. A p-value less than 0.05 was considered statistically significant. Axial load to failure data and stiffness data revealed that intramedullary nails are significantly stronger and stiffer than other devices, however there was no statistically significant difference axially between the nail thicknesses. In bending, load to failure revealed that 18G nails are significantly stronger than 20G. We concluded that 18G nail is superior to the other fixation devices, therefore it has been used for in-vivo experiments to create a novel model of atrophic non-union with stable fixation

There is a growing trend towards using pre-clinical models of atrophic non-union. This study investigated different fixation devices, by comparing the mechanical stability at the fracture site of tibia bone fixed by either intramedullary nail, compression plate or external fixator. 40 tibias from adult male Wistar rats' cadavers were osteotomised at the mid-shaft and a gap of 1 mm was created and maintained at the fracture site to simulate criteria of atrophic non-union model. These were divided into five groups (n=8 in each): the first group was fixed with 20G intramedullary nail, the second group with 18G nail, the third group with 4-hole plate, the fourth group with 6-hole plate, and the fifth group with external fixator. Tibia was harvested by leg disarticulation from the knee and ankle joints, the soft tissues were carefully removed from the leg, and tibias were kept hydrated throughout the experiment. Each group was then subdivided into two subgroups for mechanical testing: one for axial loading (n=4) and one for 4-point bending (n=4). Statistical analysis was carried out by ANOVA with a fisher post-hoc comparison between groups. A p-value less than 0.05 was considered statistically significant. Axial load to failure data and stiffness data revealed that intramedullary nails are significantly stronger and stiffer than other devices, however there was no statistically significant difference axially between the nail thicknesses. In bending, load to failure revealed that 18G nails are significantly stronger than 20G. We concluded that 18G nail is superior to the other fixation devices, therefore it has been used for in-vivo experiments to create a novel model of atrophic non-union with stable fixation

Nonunions occur in situations with interrupted fracture healing process and indicate conditions where the fracture has no potential to heal without further intervention. Per definition, no healing is detected nine months post operation and there is no visible progress of healing over the last three months. The classification of nonunions as hypertrophic, oligotrophic, atrophic and pseudoarthosis, as well as aseptic or septic, identifies mechanical and biological requirements for fracture healing that have not been met. The overall treatment strategy comprises identification and elimination of the problems. However, current clinical methods to determine the state of healing are based on highly subjective radiographic evaluation or clinical examination. A data collection telemetric system for objective continuous measurement of the load carried by a bridging smart implant was developed to assess the mechanical stability and monitor bone healing in complicated fracture situations. The first results from a clinical trial show that the system is capable to offer early warning of nonunions or poor fracture healing. Nonunions are often multifactorial in nature and not just related to a biomechanical problem. Their successful treatment requires consideration of both biological and mechanical aspects. Disturbed vascularity and stability are the most important factors. Infection could be another complicating factor resulting in unpredictable long-time treatment. New technologies for monitoring of fracture healing in addition to radiographic evaluation and clinical examination seem to be promising for early detection of nonunions

Objectives . Rotator cuff tears are among the most common and debilitating upper extremity injuries. Chronic cuff tears result in atrophy and an infiltration of fat into the muscle, a condition commonly referred to as ‘fatty degeneration’. While stem cell therapies hold promise for the treatment of cuff tears, a suitable immunodeficient animal model that could be used to study human or other xenograft-based therapies for the treatment of rotator cuff injuries had not previously been identified. Methods . A full-thickness, massive supraspinatus and infraspinatus tear was induced in adult T-cell deficient rats. We hypothesised that, compared with controls, 28 days after inducing a tear we would observe a decrease in muscle force production, an accumulation of type IIB fibres, and an upregulation in the expression of genes involved with muscle atrophy, fibrosis and inflammation. Results . Chronic cuff tears in nude rats resulted in a 30% to 40% decrease in muscle mass, a 23% reduction in production of muscle force, and an induction of genes that regulate atrophy, fibrosis, lipid accumulation, inflammation and macrophage recruitment. Marked large lipid droplet accumulation was also present. Conclusions . The extent of degenerative changes in nude rats was similar to what was observed in T-cell competent rats. T cells may not play an important role in regulating muscle degeneration following chronic muscle unloading. The general similarities between nude and T-cell competent rats suggest the nude rat is likely an appropriate preclinical model for the study of xenografts that have the potential to enhance the treatment of chronically torn rotator cuff muscles. Cite this article: Bone Joint Res 2014;3:262–72

It is supposed that disturbed vascularization is a major cause for the development of an atrophic non-union. However, an actual study revealed normal vessel formation in human non-union tissues [1]. An animal study using an atrophic non-union model should clarify the influence of the inhibition of angiogenesis by the inhibitor Fumagillin on bone healing and the underlying processes including inflammation, chondrogenesis, angiogenesis and osteogenesis. For each group and time point (3, 7, 14, 21 and 42 days) 5–6 adult female Sprague Dawley rats were analyzed. The tibia was osteotomized and stabilized intramedullary with a k-wire coated with the drug carrier PDLLA (control group) or PDLLA +10% Fumagillin (atrophy group). Microarrays: Total-RNA were pooled per group, labeled with the Agilent single-color Quick-Amp Labeling Kit Cy3 and hybridized on Agilent SurePrint G3 Rat Gene Expression microarrays. After feature extraction and quantile normalization, relevant biological processes were identified using GeneOntology. Genes with an expression value below the 25. percentile were excluded. Heatmaps were used for visualization. The analysis of inflammatory genes revealed an upregulation of monocyte/macrophage- relevant factors such as the chemokines Ccl2 and Ccl12 and the surface marker CD14. Other factors involved in the early inflammation process such as Il1a, Tnf and Il6 were not affected. Chondrogenic markers including Collagen Type II, -IX, -X, Mmp9, Mmp13, Hapln1, Ucma, Runx2, Sox5 and -9 were downregulated in this group. Furthermore, osteogenic factors were less regulated within the middle stage of healing (day 14–21). This gene panel included Bmps, Bmp antagonists, Bmp- and Tgfb receptors, integrines and matrix proteins. qPCR analysis of angiogenic genes showed an upregulation of Angpt2, Fgf1 and -2, but not for Vegfa over the later healing time points. We demonstrated in a previous study that inhibiting angiogenesis in an osteotomy model led to a reduction in vessel formation and to the development of an atrophic non-union phenotype [2]. The microarray analysis indicated no prolonged inflammatory reaction in the atrophy group. But the upregulation of chemokines together with a delay in hematoma degradation signs to a mismatch between recruitment and demand of macrophages from the vessel system. Furthermore, chondrogenesis was completely blocked, which was shown by a downregulation of chondrogenic but also osteogenic markers being involved in chondrogenic processes. A reduced recruitment of MSCs might be a possible explanation. Although, microarray data revealed only minor expression changes regarding angiogenic genes, validation by q-PCR showed an upregulation of Angpt2, Fgf1 and -2 over the later healing time points. Due to the heterogeneity of the callus tissue it might be that variations of gene expression of a single tissue type will be masked by the expression levels of other tissue types. This issue is even more pronounced when analyzing different time points and by pooling the samples

Objectives. Rotator cuff tears are among the most frequent upper extremity injuries. Current treatment strategies do not address the poor quality of the muscle and tendon following chronic rotator cuff tears. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor that activates many genes that are important in skeletal muscle regeneration. HIF-1α is inhibited under normal physiological conditions by the HIF prolyl 4-hydroxylases (PHDs). In this study, we used a pharmacological PHD inhibitor, GSK1120360A, to enhance the activity of HIF-1α following the repair of a chronic cuff tear, and measured muscle fibre contractility, fibrosis, gene expression, and enthesis mechanics. Methods. Chronic supraspinatus tears were induced in adult rats, and repaired 28 days later. Rats received 0 mg/kg, 3 mg/kg, or 10 mg/kg GSK1120360A daily. Collagen content, contractility, fibre type distribution and size, the expression of genes involved in fibrosis, lipid accumulation, atrophy and inflammation, and the mechanical properties of the enthesis were then assessed two weeks following surgical repair. Results. At two weeks following repair, treatment groups showed increased muscle mass but there was a 15% decrease in force production in the 10 mg/kg group from controls, and no difference between the 0 mg/kg and the 3 mg/kg groups. There was a decrease in the expression of several gene transcripts related to matrix accumulation and fibrosis, and a 50% decrease in collagen content in both treated groups compared with controls. Additionally, the expression of inflammatory genes was reduced in the treated groups compared with controls. Finally, PHD inhibition improved the maximum stress and displacement to failure in repaired tendons. Conclusions. GSK1120360A resulted in improved enthesis mechanics with variable effects on muscle function. PHD inhibition may be beneficial for connective tissue injuries in which muscle atrophy has not occurred. Cite this article: J. P. Gumucio, M. D. Flood, A. Bedi, H. F. Kramer, A. J. Russell, C. L. Mendias. Inhibition of prolyl 4-hydroxylase decreases muscle fibrosis following chronic rotator cuff tear. Bone Joint Res 2017;6:57–65. DOI: 10.1302/2046-3758.61.BJR-2016-0232.R1

Muscle and tendon have an adaptive, symbiotic biomechanical relationship that is drastically altered following acute tendon injury. Such injuries, like Achilles tendon rupture (ATR), do not only lead to impairments in the resultant tendinous tissue, but also to irrecoverable atrophy in the connected muscle in series. As a result, a new relationship between muscle and tendon is established after ATR, leading to lasting functional deficits in the lower limb. It remains unclear how these develop, particularly since this imbalance may be influenced by the dependent relationship of the two tissues to each other. A further confounding factor is that tendon and muscle tissues adapt on different time scales in response to mechanical loading, such as those introduced during rehabilitation. Thus, it is warranted to perform assessments not only of the overall muscle-tendon unit, but also its constituent tissues. This presentation will discuss findings from both short-term and long-term follow-ups of ATR patients, with a focus on the recovery of gait and changes in the muscle-tendon unit tissues following ATR repair. Both the influence of the rehabilitation process and suggestions for future research directions will be additionally presented

In atrophic non-union models, a minimally invasive technique is used to deliver stem cells into the fracture site via percutaneous injection. This technique is significantly affected by a backflow leakage and the net number of cells might be reduced. The Z-track method is a technique used in clinical practice for intramuscular injections to prevent backflow leakage. We evaluated the potential of the Z-track injection technique for preventing cell loss in non-union models by determining the behaviour of observable marker fluids. Firstly, toluene blue stain was used as an injection material to allow visual detection of its distribution. Rat's cadaver legs were used and tibias were kept unbroken to ensure intact skin and overlying soft tissue. Technique includes pulling the skin over the shin of tibia towards the ankle and injection of the dye around the mid-shaft. The needle was then partially pulled back, the skin was returned to its normal position and a complete extraction of the needle was followed. Secondly, a mixture of contrast material and toluene blue was used to allow direct visual and radiological detection of the injected material into the fracture site. Ante-grade nailing of tibia via tibial tuberosity was carried out followed by a 3 point closed fracture. Injection was performed into the fracture gap similarly to the steps above. X-rays were taken to visualise the location and distribution of the injected material. Observation revealed no blue stain could be detected over the skin, X -rays revealed that the radiopaque dye remained around the tibia with no escape of the material into the superficial layers or onto the skin surface. Therefore, the number of cells delivered and maintained at a target site could be increased by the Z-track method and therefore, the therapeutic benefit of stem cell injections could be optimised with this simple technique

Appropriate in vivo models can be used to understand atrophic non-union pathophysiology. In these models, X-ray assessment is essential and a reliable good quality images are vital in order to detect any hidden callus formation or deficiency. However, the radiographic results are often variable and highly dependent on rotation and positioning from the detector/film. Therefore, standardised A-P and lateral x-ray views are essential for providing a full radiological picture and for reliably assessing the degree of fracture union. We established and evaluated a method for standardised imaging of the lower limb and for reliably obtaining two perpendicular views (e.g. true A-P and true lateral views). The normal position of fibula in murine models is posterolateral to the tibia, therefore, a proper technique must show fibula in both views. In order to obtain the correct position, the knee joint and ankle joints were flexed to 90 degrees and the foot was placed in a perpendicular direction with the x-ray film. To achieve this, a leg holder was made and used to hold the foot and the knee while the body was in the supine position. Lateral views were obtained by putting the foot parallel to the x-ray film. Adult Wister rat cadavers were used and serial x-rays were taken. A-P view in supine position showed the upper part of the fibula clearly, however, there was an unavoidable degree of external rotation in the whole lower limb, and the lower part of the fibula appeared behind the tibia. Therefore, a true A-P view whilst the body was in the supine position was difficult. To overcome this, a P-A view of the leg was performed with the body prone position, this allowed both upper and lower parts of the fibula to appear clearly in both views. This method provides two true perpendicular views (P-A and lateral) and helped to optimise radiological assessment

Background. Active therapeutic exercises during unstable and unilateral conditions using body weight for resistance are often used in the rehabilitation of low back pain (LBP). In LBP patient's unilateral atrophy of the spinal muscles is reported. To address these deficits understanding side to side muscle activity using surface Electromyography (SEMG) can help clinicians design exercises that specifically address these deficits. Aim: To identify the effects of unilateral and unstable bridging exercises on trunk muscle activity. Methods. Using a repeated measures design, SEMG side to side measurements of lumbar Multifidus (MF), Iliocostalis Thoracis (ICT), Rectus Abdominis (RA) and External Oblique (EO) were conducted on 20 healthy subjects (16 female, age 25.45±3.57 years, height 166±0.8 cm, weight 63.35±12.70 kg. Mean Body Mass Index 23) during 8 supine bridging exercises with stable, unstable and unilateral conditions. Results. Muscle activity was significantly influenced by unilateral and unstable conditions. Highest SEMG activity was found in MF and ICT, lowest in RA and EO in all exercises. Highest SEMG activity of all investigated muscles was found during all unstable or unilateral conditions and lowest activity during standard bridging exercises. Unilateral exercises increased ipsilateral EMG activity on the unsupported side of all investigated muscles. Conclusion. The results suggest that unilateral atrophied muscles can be specifically trained by using unilateral bridging exercises. The intensity of the exercises can be adapted to subjects' ability by including various unstable or unilateral conditions within the bridging exercise, since individual muscle activity ranges from low to high activity between the exercises. Conflicts of Interest. None. Source of Funding. None. I confirm that this abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Summary Statement. Prophylactic vertebroplasty treatment of ‘at-risk’ vertebrae may reduce fracture risk, however which areas weaken, thus providing surgical targets? Direct spatial 3D mapping of ReTm overcomes the constraints of 2D histology, and by application may provide insight into specific regional atrophy. Introduction. Insidious bone loss with age makes the skeleton fracture-prone in the rapidly expanding elderly population. Diagnosis of osteoporosis is often made after irreversible damage has occurred. There are over 300,000 new fragility fractures annually in the UK, more than 120,000 of these being vertebral compression fractures (VCF). Some VCFs cause life-altering pain, requiring surgical intervention. Vertebroplasty is a minimally invasive procedure whereby bone cement is injected into the damaged vertebral body with the aim of stabilisation and pain alleviation. However, vertebroplasty can alter the biomechanics of the spine, apparently leaving adjacent vertebrae with an increased VCF risk. Prophylactic augmentation of intact, though ‘at-risk’, vertebrae may reduce the risk of adverse effects. The question therefore arises as to which areas of a non-fractured vertebral body, structurally weakened with age, and thus should be targeted. Frequent reports of an overlap in BMD (bone mineral density) between fracture and non-fracture subjects suggest the combination of bone quantity and its ‘quality’ (microarchitectural strength) may be a more reliable fracture predictor than BMD alone. Providing a reliable method of cancellous connectivity measurement (a highly significant bone strength factor) is challenging. Traditional histological methods for microarchitectural interconnection are limited as they usually indirectly extrapolate 3D structure from thin (8 µm) 2D undecalcified sections. To address this difficulty, Aaron et al (2000) developed a novel, thick (300 µm) slicing and superficial staining procedure, whereby unstained real (not stained planar artifactual) trabecular termini (ReTm) are identified directly within their 3D context. The aim of this study was to automate a method of identifying trabecular regions of weakness in vertebral bodies from ageing spines. Patients and methods. 27 Embalmed cadaveric vertebral bodies (T10-L3) from 5 women (93.2±8.6 years) and 3 men (90±4.4 years) were scanned by µCT (micro-computerised tomography; µCT80, Scanco Medical, Switzerland, 74 µm voxel size), before plastic-embedding, slicing (300µm thick), and surface-staining with the von Kossa (2% silver nitrate) stain. The ReTm were mapped using light microscopy, recording their coordinates using the integrated stage, mapping them within nine defined sectors to demonstrate any apparent loci of structural disconnectivity that may cause weakness disproportionate to the bone loss. A transparent 3D envelope corresponding to the cortex, was constructed using code developed in-house (Matlab 7.3, Mathworks, USA), and was modulated and validated by overlay of the previous µCT scan and the coordinate data. Results. The ReTm distribution was found to be remarkably heterogeneous (p<0.05) and independent of the bone volume (p<0.05). For example, there was preliminary evidence of central endplate disconnection predominantly in the selected preparations. Discussion/Conclusion. Such automated spatial mapping of the ReTm within a 3D framework overcomes the constraints of 2D histology. By application of this new automated method, patterns of trabecular disconnection in the spine may now provide insight into specific regional atrophy, perhaps explaining why some vertebrae fracture while others with the same BMD do not, and indicating better targets for prophylactic vertebroplasty

The re-establishment of vascularity is an early event in fracture healing; upregulation of angiogenesis may therefore promote the formation of bone. We have investigated the capacity of vascular endothelial growth factor (VEGF) to stimulate the formation of bone in an experimental atrophic nonunion model. Three groups of eight rabbits underwent a standard nonunion operation. This was followed by interfragmentary deposition of 100 μg VEGF, carrier alone or autograft. After seven weeks, torsional failure tests and callus size confirmed that VEGF-treated osteotomies had united whereas the carrier-treated osteotomies failed to unite. The biomechanical properties of the groups treated with VEGF and autograft were identical. There was no difference in bone blood flow. We considered that VEGF stimulated the formation of competent bone in an environment deprived of its normal vascularisation and osteoprogenitor cell supply. It could be used to enhance the healing of fractures predisposed to nonunion